“Friends With Kids” is a surprisingly funny and sweet film that manages to capture many of the ways in which parenthood can go right and wrong, while mostly resisting the host of tired tropes that can infect such comedies. What makes it all the more impressive is that writer-director Jennifer Westfeldt, who also stars in the film, so deftly captures parenthood despite never having had a child herself.

Westfeldt plays Julie, a 30-something professional living in New York City who’s love life has for years been almost non-existent following the break-up of a 9-year relationship. Her best friend is Jason (Adam Scott), another NYC professional, who lives in the same uptown apartment building and is a serial dater with a preference for large-breasted women. It’s clear from the opening scene that these two are soul mates and will eventually wind up together.

While the film begins and ends with strong echoes of “When Harry Met Sally,” the middle goes in an entirely different direction. When his birthday party is torpedoed by the manic lives of their friends with kids, the two commiserate about how they both want kids, but neither wants the lives their FWKs are living. So they do what any sensible people would do—they decide to have a kid together while remaining just friends. This idea is met with supportive dismay by the two couples that make up their four best friends, Leslie (Maya Rudolph) and Alex (Chris O’Dowd in his best performance yet, though his accent remains vexing), and Missy (Kristen Wiig) and Ben (Jon Hamm, Westfeldt’s real-life special friend of 15 years).

Like most parents, Julie and Jason fall off the grid for a time as the recalibrate their lives, so when they finally do have their friends over, the four veteran parents assume it’s because they’ve been embarrassed by how overwhelmed they’ve been by parenting. Nope. Westfeldt understands that having a child doesn’t have to mean there’s blood on the walls and tear-streaked mascara running down your cheeks, despite how your more traditional (which is to say “lazy”) may portray it. Which makes Westfeldt’s one concession to the zeitgeist—a fecal-splattered Jason wrestling a diaper onto his son—all the more disappointing. Does this ever happen?

But of course things start to get weird when they each begin dating again, Jason hooking up with a Broadway dancer named Jane (Megan Fox) and Julie with a divorced bohunk with kids of his own, named Kurt (Ed Burns). And things get weirder still when the two old couples and the two newly minted couples go away to Vermont for a weekend of skiing.

Though the film’s conclusion is obvious from the opening credits, Westfeldt’s keen eye and ear make “Friends With Kids” much more than your ho-hum indie romcom. All four couples she creates are totally believable and distinct from one another, each struggling with their own flavor of adulthood.

The film also gets an incredible lift from its cast. Hamm is on familiar ground as a self-medicated man wondering where all the fun went, but Ben is no Don Draper redux, and O’Dowd is hilarious giving voice to sanity as the every-dude. And Westfeldt is excellent as a woman haunted by a ticking clock, who is then suddenly jolted awake to the sound of a screaming baby, perfectly capturing the insecurity that can consume a parent.

But it’s Adam Scott that really shines here. Best known for his comedy work in films like “Step Brothers” or on “Parks & Recreation,” Scott has also done great dramatic work, most recently in “The Vicious Kind.” In “Friends With Kids” he draws on both skill sets, whether he’s gleefully waxing about how hot Jane is or delivering to Ben a brutal takedown about how right he was to have a baby with Julie. It’s not a star-making turn—this is too small a film for that—but a reminder to anyone paying attention of just how good this guy is.

Observant and touching, “Friends With Kids” is that rare comedy that not only has brain, but something to say, and makes you wonder which is more weird: that Westfeldt had never directed before or never had a kid?

"Friends with Kids" opens in theaters everywhere today

Published at 6:34 AM PST on Mar 9, 2012 | Updated at 11:43 AM PDT on May 30, 2012